In Peru, the HIV epidemic is primarily concentrated among men who have sex with men (MSM). The Peruvian government's response to the HIV epidemic has primarily focused on a subset of MSM who can be identified through peer outreach. This is an appropriate use of their limited resources;however, these efforts do not reach all MSM, especially men who have sex with men and women (MSMW). The recent increase of female cases of HIV, evidenced by the change in the male to female ratio from 10:1 in the early 1990's to 3:1 today and that HIV risk among women is influenced by the sexual behavior of their male partner, including bisexual behavior demonstrate the importance of understanding the behavior of MSMW in this setting. Our previous research in Peru identified a sub-population of young, un- or underemployed, high-risk men, referred to as "esquineros" (or 'Corner Men'), who are heterosexually-identified, but report much higher levels of bisexual behavior than the general population. This study proposes to further describe this sub-population in order to characterize their role in the HIV epidemic as well as determining the efficacy of the NIMH Collaborative HIV/STD Prevention Trial among them. The goal of this HIV/STD Prevention Trial was to test the efficacy of the Community Popular Opinion Leader (CPOL) intervention, which is based on the "Diffusion of Innovations" theory. The intervention worked to change community norms by training community popular opinion leaders to act as innovators of condom use behaviors to influence condom use increases among the peers. This trial was conducted between 2003 and 2007 among esquineros aged 18-40 years in three coastal Peruvian cities: Lima, Trujillo and Chiclayo. The proposed study is not part of the planned statistical analysis of the parent trial and will be the only in depth analysis of the effect of the CPOL trial on the esquinero sub-population. Aim 1: Identify subgroups among the esquineros based on differences in HIV/STI prevalence and sexual risk behavior as defined by partner selection (e.g. men only, women and men, or women only) and partner concurrency as well as alcohol/drug use prior to sex using baseline data. Aim 2: Demonstrate the effect of the CPOL intervention on sexual risk behavior. We hypothesize that unprotected sex with a non-primary partner in the past 3 months will decrease among esquineros in intervention communities versus control community. Aim 3: Demonstrate the effect of the CPOL intervention among subgroups of esquineros identified in Aim 1, sub-group identification is hypothesized to modify the effect of the intervention. PUBLIC HEALTH RELEVANCE: The proposed study will lead to further information on this newly identified high-risk, sub-population and to characterize their role in the HIV epidemic in Peru.